Cisco | uBR904 | Update to the Cisco uBR904 Cable Modem Installation and

Doc. No. 78-5489-01
Update to the Cisco uBR904
Cable Modem Installation and
Configuration Guide
Product Number: uBR904
This document describes the tests performed, test results, and caveats related to the Multimedia
Cable Network Partners, Ltd. (MCNS) Data Over Cable Service Interface Specification (DOCIS)
compatibility for the Cisco uBR904 cable modem.
Cisco uBR904 MCNS DOCSIS Compatibility
Table 1 lists the test results that were used to confirm MCNS DOCIS compatibility of the uBR904.
Note All adjacent channel interference results are measured both at the downstream receiver
(demodulator) and before the tuner (at the cable plant) of Cisco uBR904 cable modems.
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Table 1
CIsco uBR904 MCNS DOCSIS Compatibility Test Matrix
MCNS DOCSIS Compatibility Testing (BER1 < or = 1 x 10-8)
Tests Performed
SNR2 at Downstream Receiver
Data Rate
Adjacent Channel Interference
256 QAM3 (5.360 Msps4, alpha 0.12)
30 dB
33 dB
30 dB5
30.5 dB6
31 dB7
33 dB5
33.5 dB6
34 dB7
64 QAM3 (5.057 Msps4, alpha 0.18)
23.5 dB
23.5 dB
23.5 dB8
23.7 dB7
23.5 dB8
23.7 dB7
16 QAM3 (1.280 Msps4, alpha 0.25)
30 dB
30 dB
QPSK9 (1.280 Msps4, alpha 0.18)
30 dB
30 dB
BER = bit error rate.
SNR = signal-to-noise ratio.
QAM = quadrature amplitude modulation.
Msps = Megasymbols per second. A symbol is the basic unit of modulation.
Analog or digital adjacent channel, 0 decibels relative to carrier (dBc) located at 6MHz from the desired channel.
Analog adjacent channel, 10 dBc located at 6MHz from the desired channel.
Digital adjacent channel, 10 dBc located at 6MHz from the desired channel.
Analog adjacent channel (10 dBc) or digital adjacent channel (0 dBc) located at 6MHz from the desired channel.
QPSK = quadrature phase shift keying.
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2 Update to the Cisco uBR904 Cable Modem Installation and Configuration Guide
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Update to the Cisco uBR904 Cable Modem Installation and Configuration Guide
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4 Update to the Cisco uBR904 Cable Modem Installation and Configuration Guide
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